The following table shows changes in storage. Some of the changes are performance related like hot add of storage. This helps performance by reducing the time it takes to add new storage. The big things to note are increases in IO Sizes passed from VM’s and huge improvements in Dynamic VHDs.

Virtualization Feature

WS08 + RTM Hyper-V

WS08 SP2 Hyper-V

Windows Server 2008 R2 Hyper-V

Dynamic VHD Performance

Writes 3x slower than fixed. This is due to limited meta data caching.

Writes 3x slower than fixed. This is due to limited meta data caching.